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Lindell Audio 500 Series

Modular Analogue Outboard System By Matt Houghton
Published October 2013

Lindell Audio 500 Series

Tobias Lindell's latest range aims to deliver pro-quality outboard processing at a price that's within reach of the home studio masses.

Turn the clock back only 10 years and you'd see plenty of new outboard gear, aimed squarely at the home recordist, with budget preamps, compressors, EQs and channel strips a-plenty. How times change; for various reasons (the improvements in the on-board preamps of budget audio interfaces and of plug-in processors, and the sheer number of second-hand budget units now available) there just doesn't seem to be the same demand for cheap gear today. The emergence of so many 'boutique' companies on the other hand suggests that the appetite for high-quality hardware is stronger than ever, and conversations I've had with manufacturers and retailers indicates that the 500-series format is proving increasingly popular on both sides of the Atlantic.

Making 'Boutique' Affordable

Yet, while the 500 series has long held out the promise of making quality gear more affordable, for the most part the prices have remained stubbornly high; an established-brand chassis/power supply can seem a daunting investment if you can only afford a couple of modules to get started. Lindell Audio are one of a handful of companies that are trying to change that, by making high-quality 500-series gear that is affordable.

In fact, Tobias Lindell's objective seems to have been to see just how far down the price of a 500-series system could be pushed without compromising on the quality. With the resulting system, it still costs a shade over $1200almost £1000 to build a full mono channel strip comprising mic pre and shelving filters, EQ and compression. So while we're not talking bargain basement here, a full system is at least within reach of the average home-studio recordist and, importantly, the low price of the chassis means that it's possible to start building a system in piecemeal fashion.

Also important is that the quality is far better than that price tag suggests, with recognised-brand components, hand-wound transformers and even discrete op-amps all evident. In fact, few (if any) corners seem to have been cut, and Lindell tells me that he's only been able to keep the price low due to the scale of manufacture. So, let's look at just what you get for your money...

I've Got The Power!

Lindell has succeeded in making his modules both pleasant to look at and functional, with plenty of space for fingers to get in and tweak and a generous 20-LED gain-reduction meter on the compressor.Lindell has succeeded in making his modules both pleasant to look at and functional, with plenty of space for fingers to get in and tweak and a generous 20-LED gain-reduction meter on the compressor.

I'll discuss the modules later, but first up we have the 506 Power, which is a no-frills six-slot 500-series chassis. Given the price, it's more stylish than I'd have imagined, with a sturdy brushed aluminium case, which I suspect is less likely to suffer from dents or bending in the way my API chassis does so easily. There's a very slight curve to the exterior of the aluminium box, making it thicker in the middle and thus increasing rigidity. What I initially thought to be guide rails to make module location easier — as used in Radial's excellent, but more expensive, Workhorse — turned out to be holes for the screws! To be fair, I'd not expected to see guide rails at this price.

There are no carry handles, but Lindell do provide a snug-fitting soft neoprene carry case, which is a nice touch. The whole chassis is narrower than the equivalent API box, something which has been achieved by making it deeper to accommodate the on-board PSU in the back of the unit. Power-on indication is via a trio of LEDs on the rear panel, which, when lit, inform you that the ±16V rails and the 48V phantom power supply are ready for work. There's easy access to the PSU's fuse and an on/off switch adjacent to its IEC inlet. The PSU itself can accept a 100V to 250V AC supply, and it makes available a whopping 400mA of current per module slot on average, which compares very favourably with the 215mA of the current API equivalent and the 267mA of Radial's equivalent chassis. Of course, 400mA is overkill for any modules meeting the 500-series VPR Alliance specification, but it can't hurt, and means that pretty much any current-hungry third-party modules or DIY projects that don't confirm to the standards can be accommodated. Reassuringly, there's overload and short-circuit protection too.

The rear of the chassis may appear pretty Spartan, but it does the job it sets out to do!The rear of the chassis may appear pretty Spartan, but it does the job it sets out to do!The external audio I/O are presented individually as balanced analogue XLR connectors; this design lacks the DB25 D-sub connectors and two spare 'thru' channels of the current version of API's six-module chassis. This made it slightly more fiddly to integrate into my system than the API, but not massively so, and once it's set up it's not an issue at all, unless you're planning to regularly take this system out on location sessions. On the inside the EDAC connectors that deliver power and signals to the modules are gold plated. All in all, this is about as simple as it gets, and considering that, Lindell have certainly made an elegant job of it!

Tiny Trio

The three modules themselves all look simple, yet they're also attractive, with black rotary knobs contrasting nicely with the olive-bronze panel, shiny metal toggle-switches and chunky illuminated buttons. Like the chassis, they all feature gold-plated connectors. They will work in any 500-series chassis, not just Lindell's own.

Preamp & EQ: The 6X500 is a transformer-balanced single-channel mic preamp, which also features high- and low-shelving filters. The preamp is based around two discrete 990 amplifier stages, and each has an associated control on the front panel — Gain controls the first, and Output the second. Between these two stages the preamp offers up to 65dB gain in total. The high shelf is an inductor-based circuit, loosely based on the enduringly popular Pultec design. The turnover frequency is switchable between 6, 10 and 16 kHz, and the low shelf's between 30, 60 and 100 Hz. The two bands each offer boost only, and are obviously intended for gentle tonal shaping duties while recording. The boost controls are marked from 0 to 10, but this legend doesn't relate to anything meaningful other than your own recall notes — there's actually 15dB of boost on the high shelf, for example. Although the frequencies are switchable, the EQ boost controls are standard potentiometers, presumably due to the desire to keep costs down, but switched controls would add little here other than ease of recall. Also present on the front panel are green, yellow and red push buttons that switch the EQ in/out, invert the polarity and supply phantom power. Each of these buttons lights up when engaged. Finally, there's a five-segment LED meter.

Passive EQ: This next module, the PEX500, is another EQ offering. It's a passive EQ, again heavily inspired by the Pultec designs. Like 6X500, this design employs both input and output transformers, an inductor and a 990 amplifier stage. Again, this offers two bands of EQ, but this time you have control of the bandwidth and both boost and attenuation controls. The low-band boost and attenuation share a switch that sets them at 30, 60 and 100 Hz, while the high band has separate switches, offering boost at 6, 10 or 16 kHz and attenuation at 10, 15 or 20 kHz. As with the 6X500's controls, the boost/attenuation is governed by rotary pots. There's no metering here, just a power on/off LED and an EQ in/out button-cum-indicator.

FET Compressor: The compressor, an 1176-inspired FET (Field Effect Transistor) design called the 7X500, completes what the specs suggest will be an impressive modular channel strip. Like Lindell's rackmount compressors, this adds some useful functionality to the basic 1176-style circuit, including a wet/dry blend facility for instant parallel compression, and a switchable side-chain high-pass filter (off, 100Hz, 300Hz), to allow headroom-hogging bass frequencies through without forcing the compressor into pumping. As you'd expect, given the 1176-style design, there's no threshold control; the user balances the input and output level controls to achieve the desired amount of gain reduction — something that's indicated on the generous 20-LED gain reduction meter. Surprisngly, then, the front panel doesn't feel at all cluttered, and it's lovely to see designers making such effective use of the limited real estate this format provides. One thing the design does sacrifice is the number of available ratios and attack/release times. They can each be set independently to fast, medium or slow, and ratios of 4:1, 12:1 and 100:1 are available.

In Use

I'd suspected that having the PSU on-board and so close to all slots could result in unwanted noise, but I detected none whatsoever. I inserted a range of Lindell and third-party modules in it and observed no ill effects. The build quality of both the chassis and the modules seems good, and there are plenty of nice touches, such as the 990 amp boards being pin-compatible with more esoteric and expensive replacements, which could be useful should you feel the desire to do any tonal tweaking in the future. Not that you'd really need to, though: the mic pre, for example, was everything I'd hoped for from this design. It's not intended to be a neutral-sounding thing, but rather something that adds a touch of classic character and it does that job remarkably well, given the price. Its tonal character is much more in the API than the Neve ballpark — in other words, tight and in your face, while still benefitting from a slight transformer 'silkiness' that means it never gets harsh. Despite some evidence of building to a cost (eg. some surface-mount components) there's absolutely none of the dullness or bright fizzing that you might associate with preamps in this price bracket. Quite the opposite in fact: it sounds like a classic professional-quality preamp. That you also have the two-band EQ thrown in is quite remarkable really. Lindell describe the EQ as offering the 'creamiest high end you've ever heard', and while that might be over-egging it a tiny bit (I've heard some very, um, 'creamy' preamps!) the sound is distinctively Pultec-esque and the ability to shape the tone so effortlessly with EQ as you track is something I value enormously.

The PEX500 is almost everything I'd hoped for. I'll often use the Pultec bass-boost-plus-cut trick in rock and dance music on bass guitar and kick drums, as it just seems to lend a solidity to the LF-rich sounds in a very forgiving way. The PEX500 acquitted itself well in this role.

I've saved the best until last: the compressor. OK, so it's not quite an 1176, especially in terms of the degree of control you have, but it's damned close and the compromises have been well judged (fewer controls rather than lower quality). In some respects, such as the side-chain filter and blend controls, it's better than an 1176. The transformer saturates nicely when driven, and I didn't really miss the 'absent' ratios and time constants: the restrictions are theoretical, and in practice I didn't miss what wasn't there, especially given the presence of that blend control. Not bad for something that, albeit without the PSU, costs around the same as Universal Audio's software version of their 1176.


Lindell has obviously chosen to combine classic design manufacture (customising tried-and-tested circuits, and using hand-wound transformers, for example) with more modern large-scale construction techniques, such as using surface-mount components, where appropriate. He's also managed to keep things simple, avoiding incorporating unnecessary bells and whistles on the chassis, for example. In doing so, he's been able to strike a remarkably good balance between cost and quality.

Rightly or wrongly, Chinese manufacture has acquired a bad name, partly due to ill-informed snobbery, but also due to the number of 'me too' factories knocking out rebranded OEM gear by the thousand. So let me stress that there's no evidence of that being the case here: the build quality and finish of the chassis and the modules is what I'd expect to see on much pricier products, and in a few respects better than some more expensive competitors. Most importantly, though, the modules do exactly what you want them to do to the audio signals passing through them, and it's easy to make them do it! That makes this system something of a no-brainer purchase, for amateurs and pro engineers alike.

I'd ideally love to see a mid-range EQ as part of this system, but when I enquired about that I was told that there was one on the way, and a 10-slot rack too! So there can be no complaints there, or at all really, given the extremely competitive price.


There are more 500-series modules available than I could count, but the pickings at this price are slimmer. Warm Audio offer a similarly priced take on an API preamp, while Golden Age Project do a similar thing for the Neve 1073 pre and EQ. Radial also offer a range of affordable modules. When it comes to the chassis, several manufacturers make these, but Lindell's is the most affordable six-slot rack. IGS Audio offer a cost-effective 10-slot rack, along with a similar range of modules to Lindell's. For other 500-series preamps and processors on a tight budget, check out the products of Classic API, JLM Audio, Sound Skulptor and Five Fish Audio, amongst others.


  • Cheap — but not at all nasty!
  • Solidly built, yet elegant.
  • Modular approach means you can build a system as you can afford it.
  • Easy to understand and use.
  • Front panels uncrowded, with clear metering where appropriate.


  • At this price? You must be joking!


A superb entry point for the home recordist looking to get into genuine analogue processing, this suite of 500-series chassis and modules should hold appeal to more seasoned engineers too. The aggressive price has the potential to democratise the 500-series format.


6X500, 7X500 & PEX500 £229 per module. 506 Power chassis £309. Prices include VAT.

Nova Distribution +44 (0)20 3589 2530.

6X500, 7X500 & PEX500 $299 per module. 506 Power chassis $329.

Rad Distribution +1 914 523 5247.